Security Alarm / System during Storage?

[JoeUSNRET]

As you may know, my Montana was declared a total loss due to theft while in a "secure" storage facility last month. We currently have a covered storage location with easy access to back in a 40' 5th wheel which is extremely hard to find in this area. However, there is no AC power available to power the trailer while in storage and I normally take the batteries out while stored.

Please let me know if you have any suggestions to setup a security alarm or security system while a trailer is stored with no AC power available? any ideas would be appreciated and this may be helpful to others.

thanks for your assistance.